Electronic key telephone set



FIG. 1 is a front top and right side perspective view of an electronic key telephone set showing my new design;

FIG. 2 is a rear elevational view thereof;

FIGS. 3 and 4 are respectively left and right side elevational views thereof; and

FIG. 5 is a bottom plan view thereof.

The cord in FIGS. 1, 3, 4 and 5 is shown in broken lines for environmental association purpose only, and forms no part of the claimed design. 

The ornamental design for an electronic key telephone set, as shown and described. 